In ancient time during deva-kaal (reign of lords) disorders came into existence & people started facing health problems & were in urgent need of remedy.

So all the Sages & experts in those days were seeking for remedial measures.

So everyone went to Lord Bramha to seek remedial measure for itt.

Knowledge of ayurved was already in existence, Lord Brahma recited, recollected & represented it to king Daksh-Prajapati